Conforming Force Mechanism for IC Package Testing

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Solution Overview

Problem

Conventional automated test systems for integrated circuit chip packages face challenges in applying uniform force due to varying topographies, leading to potential damage and poor electrical connections, especially in lid-less designs with significant height variations between dice.

Innovation Solution

An integrated circuit chip package test system with a dynamically conformable workpress and non-conductive pusher pins that adapt to the multi-planar top surface of the chip package assembly, applying localized and independent forces to ensure robust electrical connections without damaging the components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a rigid aluminum workpress is used to apply force to the chip package, then the workpress structure is simple and easy to manufacture, but the force application becomes nonuniform due to height variations in the chip package components

Engineering Contradiction:
Improveworkpress manufacturing simplicityVSAvoidforce application uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The workpress bottom surface is segmented into multiple independent pusher pins rather than a single rigid surface. Each pusher pin can independently conform to the height variations of different chip package components (stiffeners, lids, substrates), allowing uniform force distribution across the entire chip package top surface while maintaining manufacturing simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pusher pins are designed with varying lengths to match the height variations of different chip package components. This parameter change in pin length allows each pin to reach the appropriate contact point on the chip package, ensuring uniform force application despite the non-uniform topography of the chip package components.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a rigid aluminum workpress is used to apply force, then the structure is simple, but some regions receive too much force while other regions receive insufficient force

Engineering Contradiction:
Improveworkpress structure complexityVSAvoidelectrical connection quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The workpress is segmented into multiple independent pusher pins that can individually adjust to the chip package topography. This segmentation allows force to be distributed evenly across all contact regions, preventing both over-forcement and under-forcement, thereby ensuring reliable electrical connections without damaging the chip package.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pusher pins are designed to be dynamically adjustable in length or position, allowing the workpress to adapt to varying chip package heights. This dynamic capability enables the system to maintain optimal force distribution across different regions, ensuring consistent electrical connection quality regardless of chip package variations.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If a conventional aluminum workpress is used, then manufacturing is easy, but the system cannot accommodate lid-less chip package designs with significant height variations

Engineering Contradiction:
Improveworkpress manufacturing easeVSAvoidaccommodation of different chip package designs
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The workpress uses multiple independent pusher pins instead of a single rigid surface, allowing each pin to independently accommodate different height variations in lid-less chip package designs. This segmentation provides the adaptability needed for various chip package configurations while keeping the overall system manufacturable using standard techniques.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pusher pin array design creates a universal workpress that can accommodate multiple chip package types and configurations, including traditional packaged chips and lid-less designs with significant height variations. The same workpress structure can be used across different chip package designs, providing versatility without requiring complex customizations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively reduces the risk of damage to chip packages by distributing force evenly, ensuring reliable electrical connections and minimizing the risk of component damage during testing.

Implementation Method 1

Each of the plurality of pusher pins has a spring-loaded mechanism that applies a resilient normal force to the chip package assembly

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3701273B1Balanced conforming force mechanism for integrated circuit package workpress testing systems
Publication Date: 2025.03.26 XILINX INC
  • EP3701273B1 patent drawingFigure 1A
  • EP3701273B1 patent drawingFigure 1B
  • EP3701273B1 patent drawingFigure 1C

AI summary

An integrated chip package assembly test system (100) and method for testing a chip package assembly are described herein. In one example, an integrated circuit chip package test system (100) includes a socket (120) and a workpress (106). The socket (120) is configured to receive a chip package assembly (160) for testing in the test system (100). The workpress (106) is positioned over the socket (120) and has a bottom surface (1 16) that is dynamically conformable to a multi-planar top surface topography of the chip package assembly (160).